Mercury trapped in Arctic permafrost could pose a serious risk to humans and the environment, a new study has found.

Massive amounts of mercury are naturally occurring in the icy frozen north, but with climate change warming the land, the permafrost is melting and scientists worry that this could result in significant quantities of the pollutant being released into the atmosphere, the study, published Monday in the journal Geophysical Research Letters, said.

"Prior to the start of the study, people assumed permafrost contained little to no mercury," said study co-author Kevin Schaefer of the National Snow and Ice Data Center at the University of Colorado, according to National Geographic. "But it turns out that not only is there mercury in permafrost, it's also the biggest pool of mercury on the planet."

The study documents how researchers targeted various sites in Alaska, where they drilled through 13 permafrost soil cores between 2004 and 2012.